Soldering Question – Corolla Clock Issue

[Matthew Ross]

Hey everyone,

Earlier this week I posted about a few electrical issues on a 2005 Corolla, and I solved most of them other than the broken clock. Apparently, the clock on many Corollas of this vintage have clock issues. I found a video that shows how to re-solder the resistors on the board.
Here it is:

I’ve never soldered anything in my life, so I’m thinking that this might be a good introductory project.

What kind of solder should I buy? Also, what kind of soldering iron should I buy? Do you think this job is too complex for a first-timer?

Thanks,

Matt

Topic

[Erin]

Make sure the tip of the soldering iron is very small. I would say go with at least a 30 watt iron. I have a 15 and a 30 watt iron and the 15 watt one sucks, just doesn’t produce enough heat to make projects go smooth. Radio shack has them. They are not the best irons out there but for occasional use, should be fine (Kind of like how Craftsman tools are best for the DIY mechanic, no need for snap-on or Mac)

Solder – I use 60/40 rosin core I found at radio shack. Get the thinnest stuff you can find for tiny projects.

Also get some solder wick. It looks like braided copper wire and tends to draw solder off stuff (when removing old stuff) The guy in this video should have removed the old stuff first and then cleaned up any corrosion best he could.

Soldering can be a REAL tedious task. The most important tool you will need is – steady hands.

With removing old solder, you would lay the wick on the joint you want to desolder, then place the hot iron on top and you will notice the wick starting to tin. clean up whatever corrosion with something like an old toothbrush for good measure. Then apply new solder.

If you want to practice on something else first, maybe get an old radio (working or not) from a thrift store for a few bucks and just try it. It gives the same hands-on practice as removing parts at a junk yard.

I say count on spending about $30 for a 30 watt iron and solder.

This is not an advanced project by any means. I think you can handle it.

[Matthew Ross]

Thanks for all of your help.

[James O’Hara]

Circuit boards use silver solder. Silver solder requires higher temps. Higher temps = easier to burn board. Steady hand is very useful. Radioshack sells a 45 watt solder iron that is great. Also get a pencil point tip for it. You will also need silver solder and desoldering braid. Desoldering braid is copper wires braided together put it over the solder your trying to soak up, heat it up, it pulls up the solder then remove it with the solder iron on it so it keeps the solder free flowing aka doesn’t solder the braid to the board. Try not to touch with your fingers anything other then the thins sides of the circuit board. While weller is considered the better brand for soldering iron the hard plastic handle style tends to heat up and can actually burn you which is why i like the radioshack one.

If you watch this video at 29 mins in it talks about soldering.
https://www.youtube.com/watch?v=smE5NJ0yo3o

If you are doing micro aka anything smaller then the size of a bic ball point pen i wish you the best of luck. It requires an extremely steady hand and/or very precise motor skills. If its already broken though it can’t hurt. In the video its micro soldering.

When micro soldering as soon as it starts to melt the solder remove the iron the solder pads are very easily burnt. You are going to want to steady your fingers and wrist when doing micro soldering. You can also use the technique of putting solder bubbled up on the tip of the iron and basically dragging it across the pad causing it to leave some solder behind. This is best bet if you do not have a very steady hand. Liquid solder will behave very much like water. Hope all that helps.

[Slobodan]

Make sure that soldering iron tip is chisel type (in the shape of little chisel, like 2-3 mm wide or so). The awl/spike shaped ones are no good.
Bare in mind that tips on cheap soldering irons are expendable, they wear out. So either buy spare tips, or buy good quality iron. If you are buying good quality one, make sure it has PTC heater element.
Also, those cheap irons that claim that are 50 W, for example, are not even close to that. You don’t need that much power for electronics (especially SMD), you can burn everything up.

For soldering, 350 oC iron is good, but it in not so good for desoldering. So, for you 450 oC iron will do fine (and about 25 W).

Solder wise, get leaded one. Unleaded is so much harder to work with. Get the thinest one you can. Of course, it needs to contain flux (but practically all of them do).

Also, when getting solder wick, get the one that also contains flux.

And buy some no-clean flux as well (liquid one, in the pen tipe case). Flux is a mild acid that cleans the pads of corrosion and makes soldering much more easier.

When desoldering, since all commercial boards are soldered with unleaded solder (that melts at a higher temperature), you will need (first, apply flux on it) to add some extra solder on the joint in order to have good thermal mass so you can desolder the component (actually heat up the joint) using the solder wick. Otherwise, you will just burn the component.

[Thomas Ferry]

I’m not a service technician but I am former IT professional and current eletronics hobbyist.

What Summer_Night said is 100% true and i would also like to add some more to what they said. These are surface mount components and when you remove the resistors to reapply or fix them make sure when you wick up the old solder not to damage the solder pads.

[Author]

Replies